Yovisto is a new video search engine for educational videos and e-lectures. yovisto provides a social tagging function. You can sign up at yovisto and maintain your own online lecture collections, maintain an own user profile, make friends, choose your favorite video lecture, share lecture recordings and (!) you can tag videos.

Description of yovisto ontology

Abstract

Linked Open Data has become one of the driving forces for the emerging
Semantic Web, which enables interlinking and integrating former proprietary data to
the global linked data by using RDF as a standard data format.
We have published the database of yovisto.com in RDF and made it accessible via SPARQL.

This page specifies the yovisto ontology and shows
some examples on how to use this ontology with our SPARQL endpoint.

Classes

Every video collection usually belongs to a category, as e.g., Computer Science or Physics. You can find an overview on yovisto's categories here.

Constraint

Property

exactly 1

dc:identifier

dc:title

maximal 1

skos:related

Collection:

A collection is a series of videos (videofiles) or a Podcast consisting of episodes. A collection also represents a lecture series consisting of several classes.

Collection is a part of Category.

Constraint

Property

exactly 1

dc:identifier

dc:title

dc:creator

all values from Organization

maximal 1

dc:subject

all values from Category

dc:coverage

Video

A video is a digital asset, e.g., a lecture recording.

Constraint

Property

exactly 1

dc:identifier

dc:title

dcterms:extent

dcterms:isPartOf

only Collection

maximal 1

dc:subject

all values from Category

dc:coverage

dc:description

dc:format

dc:language

dcterms:alternative

minimal 1

dc:contributer

all values from Speaker

minimal 0

mpeg7:MediaTime

VideoSegment:

A videosegement is a part of a video. Videosegments are examined with scene detection algorithms specialized on lecture recordings automatically.

VideoSegment is a part of exactly 1 Video.

Constraint

Property

exactly 1

dcterms:isPartOf

only Video

mpeg7:MediaTime

maximal 1

dc:description

dc:title

MediaTimeType:

The MediaTimeType specifies any time intervall in a video. Usually, a MediaTimeType has a start time point and a
duration. MediaTimeType is used to specify the time reference of video segments and tags in a certain video. See also: mpeg-7 ontology

MediaTimeType is a part of the mpeg7 ontology.

Constraint

Property

Multiple

mpeg7:MediaTimePoint

mpeg7:duration

tag:tag

all values from Tagging

Tagging:

Tagging describes the process when a user tags a video. See also: tag ontology

A speaker is a contributing person in the video, which is usually visible or audible.

Speaker is a subclass of foaf:Person.

Constraint

Property

exactly 1

rdfs:subClassOf

foaf:Person

dc:identifier

foaf:surname

Organization:

An organization is an university or institute where the video was created.

Organization is a subclass of foaf:Organization.

Constraint

Property

exactly 1

rdfs:subClassOf

foaf:Organization

dc:identifier

foaf:name

maximal 1

foaf:homepage

foaf:logo

User:

The user stands for a registered yovisto account.

User is a subclass of foaf:OnlineAccount.

Constraint

Property

exactly 1

rdfs:subClassOf

foaf:OnlineAccount

foaf:accountName

Usage Examples

Hints:

The classes Video and VideoSegment are linked over the property mpeg7:MediaTime to mp7:MediaTimeType
which has two properties: mp7:MediaTimePoint and mp7:duration.

Because of the allocation of tags just for a special segment in one video these segments are distinguished with these information.
So the mp7:MediaTimePoint tags the startpoint of this segment and the mp7:duration tags the duration
how long the segment is on and the tag is valid in one video.

Although Video keeps the property dcterms:extent which only means the duration of the whole video. Don't confuse it with
mp7:duration!

Examples:

The following example shows a SPARQL query which delivers the 10 most assigned tags in yovisto: